TedCrilly
Contributor
Contributor

Dormant VMs stealing resources??

Using Latest ESXI, we are getting good performance out of HP servers with 3-5 VM's on each. Question is, if I have a couple of 'Dormant' VM"s on a host, that are rarely used, without any resource pools created, looking at the resource allocation, it is spread evenly between all VM's, even the dormant ones, for example, with 5 VM's, each gets a 20% cut. Does this mean the 2 dormant (turned off) VM's are causing the 3 others to take a lower share than if I had deleted those VM's, which would give each running VM a 33% cut instead??

Hope this makes sense.

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2 Replies
Ken_Cline
Champion
Champion

Resources are not allocated on a strictly proportional basis. If a VM does not ask for resources, it will not use them. Idle VMs will consume SOME resources (to service interrupts, run background tasks, etc.), but in general, won't take much.

Ken Cline

Technical Director, Virtualization

Wells Landers

TVAR Solutions, A Wells Landers Group Company

VMware Communities User Moderator

Ken Cline VMware vExpert 2009 VMware Communities User Moderator Blogging at: http://KensVirtualReality.wordpress.com/
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taits
Enthusiast
Enthusiast

Without a defined resource pool, all VMs are in the "parent" resource pool. This means that each VM gets an equal "share" of the cluster's resources. If you have no reserves, limits, or shares defined, then as a VM needs more resources it'll have access to whatever's not being used within the cluster by the other VMs - "expandable reservation". If there is contention for memory resource, then one of the 3 memory management techniques will come into play. When a VM is turned off, even if it has a reservation for memory or CPU, the other VMs will be able to use all the resources in the cluster. Once it's turned on (or power on) then the reservations will come into account.

Hope this helps, t

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